Complexity and Emergence: Proceedings of the Annual Meeting of the International Academy of the Philosophy of Science. Bergamo, Italy 9-13 May 2001

231 Pages·2003·10.15 MB·English

by  Academie Internationale De Philosophie Des Sciences Meeting

AND
EMERGENCE
Editors
Evandro Agazzi
Luisa Montecucco
Proceedings of the Annual Meeting of the International Academy of the Philosophy of Science
COMPLEXITY
AND J
EMERGENCE
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Proceedings of the Annual Meeting of the International Academy of the Philosophy of Science
COMPLEXITY
AND
EMERGENCE
Bergamo, Italy 9-13 May 2001
Editors
Evandro Agazzi & Luisa Montecucco
University of Genoa, Italy
V fe World Scientific
«b NNeeww J Jeerrsseeyy L • oLnodnodno-nS i• nSi ingapore • Hong Kong
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COMPLEXITY AND EMERGENCE
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Contents
Introduction vii
E. Agazzi and L. Montecucco
PART I THE NOTIONS OF COMPLEXITY AND EMERGENCE
1. What is Complexity? 3
E. Agazzi
2. On Levels and Types of Complexity and Emergence 13
H. Lenk and A. Stephan
3. Formal Metatheoretical Criteria of Complexity and Emergence 29
C. U. Moulines
4. Beyond Reductionism and Holism. The Approach of
Synergetics 39
B. Kanitscheider
5. Kolmogorov Complexity 45
J. Mosterin
6. Modeles de Structures Emergentes dans les Systemes
Complexes 57
J. Petitot
PART II COMPLEXITY AND EMERGENCE IN NATURAL SCIENCE
7. Emergence in Physics: The Case of Classical Physics 75
R. Omnes
VI Complexity and Emergence
8. Classical Properties in a Quantum-Mechanical World 87
A. Cordero
9. Reduction, Integration, Emergence and Complexity in
Biological Networks 101
J. Ricard
PART III THE EMERGENCE OF THE MIND
10. Complexity and the Emergence of Meaning: Toward a
Semiophysics 115
F. T. Arecchi
11. Complexity and the Emergence of Intentionality: Some
Misconceptions 147
M. Casartelli
12. Can Supervenience Save the Mental? 161
L. Montecucco
13. From Complexity Levels to the Separate Soul 181
G.Del Re
Index 205
Introduction
Complexity has become a dominant concept in contemporary science,
especially as a consequence of the increasing impact of the perspectives of
general systems-theory. And its fruitfulness essentially consists in the fact
that it has rendered possible a deeper understanding of the functional and
structural interrelations existing within a given system and between this
system and surrounding systems. The advantage of this point of view is that
it offers conceptual tools for a more adequate understanding of the novelties
that complex systems evince with regard to their constituent parts, novelties
that are often called emergent and that give a rather precise sense to the old
maxim that "the whole is more than the sum of its parts". This "more",
however, can be interpreted according to two contrary approaches. The first
consists in maintaining that the knowledge of the parts and their properties is
sufficient to account for the new properties of the whole. Since these are
deterministically entailed by the properties of the parts, they result from
them and, in this sense, are reducible to them. The second consists in
maintaining that the properties of the parts are necessary but not sufficient to
account for the properties of the whole, since the latter are further dependent
on the occurrence of particular conditions not inscribed in the properties of
the parts, and whose contingent configuration could have led to a totally
different result if they had been only slightly different. In this sense the
second approach relies on an indeterministic view of the dynamics of natural
phenomena (which is also extended to phenomena studied in disciplines
different from the natural sciences).
This fact explains why the thematic of complexity has become more
important in the natural sciences as a consequence of the obsolescence of the
classic deterministic view and of some of its most characteristic corollaries.
The classic view is well portrayed in the famous statement of Laplace: a
superior Intelligence that could know at a given instant the exact state of the
universe (that is, the positions and velocities of all its material points) and
also know all the natural laws regulating their motion, and that in addition
could also calculate the exact solutions of the differential equations
VI1
Complexity and Emergence
Vlll
expressing these laws, would be able to predict exactly the state of the
universe (that is, the position and velocity of every material point in it) at
any future instant. Since humans are far from being endowed with such
exceptional cognitive powers, they must compensate their ignorance by
resorting to the calculus of probabilities, thanks to which they are able,
starting from a good approximation in their knowledge of the initial
conditions, to predict with an equally good approximation the knowledge of
future events. And this because a "small" change in the initial conditions was
believed to lead to a "small" change in the deterministically following final
state. This tacit postulate is known as the condition of linearity for the
physical phenomena; and it is well-known that already with Poincare this
postulate was seriously challenged in his study of the famous "three-body
problem", in which the application of the most deterministic of the laws of
physics (Newtonian gravitation) was shown to be insufficient to grant the
expected exact prediction even of the behavior of such a simple system as
that constituted by three material bodies. The awareness of the non-linearity
of the great majority of physical effects is now one of the most generally
recognized features of scientific phenomena, and appears as a direct
consequence of their complexity.
A strong aspect of the classical perspective seemed to be that it was the
best suited to account for the order and harmony of the universe. If this is
regulated by eternal, immutable and strictly deterministic laws, it is
sufficient to admit that a certain wise disposition of the initial state of the
universe was posited (perhaps by a divine intelligence, as Newton himself
had suggested), in order to be sure that this "cosmos" (that is, ordered
totality) will persist eternally and be intrinsically explorable by humans.
Within classical physics, however, this view soon appeared hardly tenable.
When the second principle of thermodynamics expressed the
"irreversibility" of thermal phenomena, the problem became that of
reconciling this feature with the time-reversibility of all the mechanical laws.
The ingenious solution elaborated by certain famous physicists of the
19th century was at the same time reductionist and probabilistic: heat and
temperature are only macroscopic magnitudes corresponding to the
mechanical kinetic energy of the molecules constituting matter, which are
subject to continuous agitation and collisions regulated by classical
reversible mechanical laws. In this interpretation something such as the
"irreversible" passage of heat from a body at a high temperature to a body at
a lower temperature was explained to be not really irreversible, but only
Introduction
IX
endowed with a very high probability. Therefore, reversibility in
thermodynamics was not theoretically excluded, but shown to be so highly
improbable a process that it should be practically excluded. In the technical
elaborations of this point two salient aspects are worth mentioning: disorder
is much more probable than order, such that the natural tendency of the
dynamic of a closed system is towards an increasing state of disorder of its
constituent parts. In terms of energy, this was expressed as a law of the
degradation of energy according to which the evolution of a closed system is
toward a state of thermal death, in which all forms of energy have been
reduced to the lowest form, i.e., to heat. Since the universe was considered a
closed system, this was the famous thesis of the thermal death of the
universe. As a conclusion of this story, the deterministic view, once it had
been applied to the understanding of complex systems and of real processes,
appeared to entail a transition from order to disorder and from stability to
death.
More appealing was the perspective elaborated in a much more intuitive
and less "rigorous" way by biology. Determinism has always been rather
alien to the conceptual space of biology, and this precisely because any
living organism is in itself such a complex entity that an exact prediction of
its behaviour is almost meaningless. The most we can do is to formulate
probabilistic predictions based on the empirical ascertainment of relative
frequencies. This general attitude was greatly reinforced by the appearance
of evolutionistic theories in the 19th century. Independently of the differences
existing among these theories concerning the postulation of the
"mechanisms" of evolution, all of them agreed on the admission (that was
also supported by empirical evidence) of the unpredictable appearance (and
extinction) of living species. In particular, novelties constituted by the
appearance of new species were accounted for by an improbable encounter
of contingent situations.
According to the Darwinian theory of natural selection (but, to a minor
degree, also according to other theories of evolution), the concurrent
presence of certain contingent "exceptional" features in a few individuals of
a given species—that also contingently happened to make them more fit vis
a-vis their environment and better able to survive in it, and which also
happened to be inherited by their descendants—would gradually lead to the
extinction of the offspring of the "normal" individuals and to the
consolidation of the new species endowed with the "favorable"
characteristics which initially occurred "by chance". According to this view,